1. MOTION Introduction

2. MOTION  Motion is defined as when an object changes position over time when compared to a reference point.  A reference point is an object that appears to stay in place.  The Earth’s surface is a common reference point when comparing objects. Other common reference points are trees or buildings. A moving object can also be used as a reference point.

3. SPEED  The rate at which an object moves depends on the distance traveled and the time taken to travel that distance  Speed is the rate at which an object travels Ex: It took 10 seconds to travel 50 meters Speed = distance/time = 50 meters/10 seconds = 5 m/s

4. AVERAGE SPEED  Most of the time objects don’t travel at a constant speed, but change speed. Think of when you’re riding a bike or driving a car somewhere. There are turns, stop signs, and traffic lights.  Average speed is the total distance traveled over the total time  Average speed = total distance/total time

5. PLEASE SOLVE:  If you walk for 2 hours and travel 500 meters per hour, what is your speed?  It takes you 10 hours to drive to Vermont and you travel 500 miles, what is your speed?  If you run for 1 hour and travel 6 miles, what is your speed?  If you walk for 1.5 hours and travel 7.5 kilometers per hour, what is your average speed?  A plane flies at a speed of 150 m/s for 10 s and 200 m/s for 5 s, what is the plane’s average speed?

6. VELOCITY  The speed of an object in a particular direction  Changes when speed or direction changes, or both Speed change: 15 m/s South to 20 m/s South Direction change: 15 m/s South to 15 m/s East Speed and direction change: 15 m/s South to 20 m/s East

7. SPEED VS. VELOCITY What’s the difference?  Speed is the amount of time it takes an object to travel a certain distance  Velocity is the amount of time it takes an object to travel a certain distance in a certain direction

8. RESULTANT VELOCITY  Velocity combines  If you’re riding in a bus traveling 15 m/s East and you stand up to walk down the aisle to the front while it is moving, are you still moving at the same velocity as the bus?  If the bus is traveling 15 m/s East and you stand up to walk down the aisle to the front at 1 m/s East, what is your resultant velocity?  If you’re riding the same bus traveling 15 m/s East and you stand up to walk down the aisle to the back at 1 m/s West, is your resultant velocity the same as above? What is your resultant velocity?

9. ACCELERATION  The rate at which velocity changes  Acceleration = final velocity – starting velocity/time it takes to change velocity

10. PLEASE SOLVE  A bird passes over point A with a velocity of 500 m/s North. 40 seconds later it passes over point B at a velocity of 10,000 m/s North. What is the plane’s acceleration from point A to point B?  A plane passes over New York with a velocity of 8,000 m/s North. An hour later it passes over Boston at a velocity of 9,000 m/s North. What is the plane’s acceleration from New York to Boston?  A coconut falls from the top of a tree and reaches a velocity of 19.6 m/s when it hits the ground. It takes 2 seconds to reach the ground. What is the coconut’s acceleration? What is the speed at which the coconut is traveling after 1 second of falling?